Irritable bowel syndrome (IBS) or spastic colon is a functional bowel disorder characterized by chronic abdominal pain, discomfort, bloating, and alteration of bowel habits in the absence of any detectable organic cause. Diarrhoea or constipation may predominate, or they may alternate (classified as IBS-D, IBS-C respectively). IBS may begin after an infection (post-infectious, IBS-PI), a stressful life event or onset of maturity without any other medical indicators. In IBS, routine clinical tests yield no abnormalities, though the bowels may be more sensitive to certain stimuli, such as balloon insufflation testing.
IBS is a very common condition affecting approximately 15% of the population at any one time. There are about twice as many women as men with this condition. IBS is a source of chronic pain, fatigue and other symptoms, and it increases a patient's medical costs, and contributes to work absenteeism. Researchers have reported that the high prevalence of IBS, in conjunction with increased costs produces a disease with a high societal cost. It is also regarded as a chronic illness and can dramatically affect the quality of a sufferer's life.
Although there is at current no cure for IBS, there are treatments which attempt to relieve symptoms, including dietary adjustments, medication and psychological interventions.
Probiotics, in particular strains of lactic acid bacteria, have been reported to be beneficial in the treatment and/or prevention of IBS. Examples of such strains are disclosed in WO 2007/036230, WO 03/010297, and WO 2009/080800.
When disruption on intestinal mucosal barrier occurs, there is a leakage of water and plasma protein into the lumen and translocation of intestinal bacteria into the systemic circulation. These factors contribute typically to the development of local inflammations or even worse of systemic septicaemia. Bacterial LipoPolySaccharide (LPS) is known to cause mucosal hyperpermeability in vivo. LPS was found to promote gut barrier dysfunction through an oxidative mechanism and to lead to an increase in permeability which can be evaluated by measuring the difference in potential observed from the apical and basal sides of the monolayer, called the Trans Epithelial Electrical Resistance (TEER). Increasing evidence suggests that some probiotic and commensal bacteria ameliorate intestinal barrier impairment (decreasing the permeability) in vitro (Resta-Lenert and Barrett, 2006; Miyauchi et al., 2008) and in vivo, and help in relieving IBS and IBD symptoms. Lactobacilli and bifidobacteria were analyzed for this property (via TEER evaluation). It appears from this study that the increase of barrier resistance measured by TEER is strain dependant. There is a need for further strains that favor barrier integrity and/or decrease permeability, typically as evidence by TEER evaluations. There is a need for strains that improve such properties.